The present invention relates to pre-treatment of cellulosic biomass feedstocks such as: agricultural residues, e.g., corn stalks, corn stover, hulls, cereal straws; energy plants, e.g., high yielding grasses including switch grass, miscanthus and energy cane; and forest and sawmill residues, e.g., wood chips and shredded thinnings. The pre-treatment includes pre-hydrolysis and possibly steam explosion to extract the carbon sugars for the further production of bio-fuels and chemicals. The pretreatment process may be followed by other conventional treatments, such as generation of alcohol for biofuels or other chemicals.
Pre-hydrolysis and auto-hydrolysis typically refer to cooking cellulosic biomass feedstocks at temperatures of, for example, 110 to 190 degrees Celsius (° C.) for approximately 10 to 60 minutes (min.), where an acid solution in the vessel dissolves and hydrolyses hemi-cellulose in the feedstock to C5 sugars (such as xylose and arabinose), as well as amorphous C6 sugars. The pre-hydrolysis and auto-hydrolysis of soft-wood hemi-cellulose generally results in mostly gluco-mannan being dissolved and hydrolyzed. Mild acids, SO2-gas, oxygen, compressed air, ammonia or other catalyzing agents may be added to the cooking vessel to enhance the hydrolysis of hemi-cellulose